Efficient and Rapid generation of neural stem cells by direct conversion Fibroblasts with A Single microRNA

Abstract

Neural stem cells (NSCs) have great potential in the application of neurodegenerative disease therapy, drug screening and disease modeling. NSC can be generated by reprogramming from terminally differentiated cells with transcription factors or small molecules. However, current methods for producing NSCs involve the danger of integrating foreign genes into the genome and the problem of low efficiency. Here, we report an efficient method to generate NSCs from human skin-derived fibroblasts with microRNA (mir-302a) in 2-3 days. The induced NSCs (iNSCs) have more than 90% of purity. Their morphology is similar to regular NSCs, expressing key markers including Nestin, Pax6 and Sox2, and can be expanded for more than 20 passages in vitro. They can also differentiate into functional neuron progeny, astrocytes and oligodendrocytes as well. Those cells can elicit action potential, can be xeno-transplanted into the brain of immune-deficient mice, and can survive and differentiate in vivo without tumor formation. This study shows that a single part of pluripotency-inducing mir-302 cluster can drive fibroblasts reprogramming, providing a general platform for high-efficiency generation of individual-specific human NSCs for studies of neuron system development and regenerative cell therapy.